The present invention relates to a UV-blocking or cutoff filter, comprising a disk-shaped glass body, which is provided with paint or coloring that blocks ultraviolet radiation, but transmits visible light and infrared radiation.
This type of filter that blocks ultraviolet light (UV) is used in many different technical fields, for example in photography, but there are also industrial applications, for example in drying process with infrared light in automobile body repair shops.
It is known to make the above-described UV-blocking filter by coloring glass in the melt, forming a glass plate from the melt and cutting the filter out from the resulting glass plate. However the step of coloring the melt is very expensive and thus only economical in mass production.
It is also known to apply an ultraviolet blocking coating to a glass body for the filter with an appropriate coating process, for example a CVD method. However this sort of UV-blocking filter can only bear a thermal load to a limited extent.